iSharkFly-Docs
/
java-tutorials
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Merge pull request #12456 from hkhan/JAVA-12757-update-opencsv-code 

[JAVA-12757] Update code for OpenCSV article
This commit is contained in:
kwoyke 2022-07-08 10:38:26 +02:00 committed by GitHub
parent 2fe4ccbead f7c39d586e
commit 0eb9cfbad8
10 changed files with 212 additions and 253 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

121
libraries-data-io/src/main/java/com/baeldung/libraries/opencsv/Application.java
View File

@ -1,5 +1,6 @@
package com.baeldung.libraries.opencsv;
import com.baeldung.libraries.opencsv.beans.CsvBean;
import com.baeldung.libraries.opencsv.beans.NamedColumnBean;
import com.baeldung.libraries.opencsv.beans.SimplePositionBean;
import com.baeldung.libraries.opencsv.examples.sync.BeanExamples;
@ -7,102 +8,60 @@ import com.baeldung.libraries.opencsv.examples.sync.CsvReaderExamples;
import com.baeldung.libraries.opencsv.examples.sync.CsvWriterExamples;
import com.baeldung.libraries.opencsv.helpers.Helpers;
import java.io.Reader;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.List;
public class Application {
/*
* Bean Examples.
*/
public static String simpleSyncPositionBeanExample() {
Path path = null;
try {
path = Helpers.twoColumnCsvPath();
} catch (Exception ex) {
Helpers.err(ex);
}
return BeanExamples.beanBuilderExample(path, SimplePositionBean.class).toString();
// CSV Reader Examples
public static List<String[]> readLineByLineSyncExample() throws Exception {
Path path = Helpers.twoColumnCsvPath();
return CsvReaderExamples.readLineByLine(path);
}
public static String namedSyncColumnBeanExample() {
Path path = null;
try {
path = Helpers.namedColumnCsvPath();
} catch (Exception ex) {
Helpers.err(ex);
}
return BeanExamples.beanBuilderExample(path, NamedColumnBean.class).toString();
public static List<String[]> readAllLinesSyncExample() throws Exception {
Path path = Helpers.twoColumnCsvPath();
return CsvReaderExamples.readAllLines(path);
}
public static String writeSyncCsvFromBeanExample() {
Path path = null;
try {
path = Helpers.fileOutBeanPath();
} catch (Exception ex) {
Helpers.err(ex);
// CSV Writer Examples
public static String writeLineByLineSyncExample() throws Exception {
Path path = Helpers.fileOutOnePath();
return CsvWriterExamples.writeLineByLine(Helpers.fourColumnCsvString(), path);
}
public static String writeAllLinesSyncExample() throws Exception {
Path path = Helpers.fileOutAllPath();
return CsvWriterExamples.writeAllLines(Helpers.fourColumnCsvString(), path);
}
// Bean Examples
public static List<CsvBean> simpleSyncPositionBeanExample() throws Exception {
Path path = Helpers.twoColumnCsvPath();
return BeanExamples.beanBuilderExample(path, SimplePositionBean.class);
}
public static List<CsvBean> namedSyncColumnBeanExample() throws Exception {
Path path = Helpers.namedColumnCsvPath();
return BeanExamples.beanBuilderExample(path, NamedColumnBean.class);
}
public static String writeSyncCsvFromBeanExample() throws Exception {
Path path = Helpers.fileOutBeanPath();
return BeanExamples.writeCsvFromBean(path);
}
/*
* CSV Reader Examples.
*/
public static String oneByOneSyncExample() {
Reader reader = null;
try {
reader = Files.newBufferedReader(Helpers.twoColumnCsvPath());
} catch (Exception ex) {
Helpers.err(ex);
}
return CsvReaderExamples.oneByOne(reader).toString();
}
public static String readAllSyncExample() {
Reader reader = null;
try {
reader = Files.newBufferedReader(Helpers.twoColumnCsvPath());
} catch (Exception ex) {
Helpers.err(ex);
}
return CsvReaderExamples.readAll(reader).toString();
}
/*
* CSV Writer Examples.
*/
public static String csvWriterSyncOneByOne() {
Path path = null;
try {
path = Helpers.fileOutOnePath();
} catch (Exception ex) {
Helpers.err(ex);
}
return CsvWriterExamples.csvWriterOneByOne(Helpers.fourColumnCsvString(), path);
}
public static String csvWriterSyncAll() {
Path path = null;
try {
path = Helpers.fileOutAllPath();
} catch (Exception ex) {
Helpers.err(ex);
}
return CsvWriterExamples.csvWriterAll(Helpers.fourColumnCsvString(), path);
}
public static void main(String[] args) {
try {
simpleSyncPositionBeanExample();
namedSyncColumnBeanExample();
writeSyncCsvFromBeanExample();
oneByOneSyncExample();
readAllSyncExample();
csvWriterSyncOneByOne();
csvWriterSyncAll();
readLineByLineSyncExample();
readAllLinesSyncExample();
writeLineByLineSyncExample();
writeAllLinesSyncExample();
} catch (Exception e) {
throw new RuntimeException("Error during csv processing", e);
}
}
}

5
libraries-data-io/src/main/java/com/baeldung/libraries/opencsv/beans/NamedColumnBean.java
View File

@ -27,5 +27,10 @@ public class NamedColumnBean extends CsvBean {
this.age = age;
}
@Override
public String toString() {
return name + ',' + age;
}
}

4
libraries-data-io/src/main/java/com/baeldung/libraries/opencsv/beans/SimplePositionBean.java
View File

@ -26,4 +26,8 @@ public class SimplePositionBean extends CsvBean {
this.exampleColTwo = exampleColTwo;
}
@Override
public String toString() {
return exampleColOne + ',' + exampleColTwo;
}
}

5
libraries-data-io/src/main/java/com/baeldung/libraries/opencsv/beans/WriteExampleBean.java
View File

@ -37,4 +37,9 @@ public class WriteExampleBean extends CsvBean {
public void setColC(String colC) {
this.colC = colC;
}
@Override
public String toString() {
return colA + ',' + colB + "," + colC;
}
}

53
libraries-data-io/src/main/java/com/baeldung/libraries/opencsv/examples/sync/BeanExamples.java
View File

@ -4,60 +4,49 @@ import com.baeldung.libraries.opencsv.beans.CsvBean;
import com.baeldung.libraries.opencsv.beans.WriteExampleBean;
import com.baeldung.libraries.opencsv.helpers.Helpers;
import com.baeldung.libraries.opencsv.pojos.CsvTransfer;
import com.opencsv.CSVWriter;
import com.opencsv.bean.*;
import com.opencsv.bean.CsvToBean;
import com.opencsv.bean.CsvToBeanBuilder;
import com.opencsv.bean.StatefulBeanToCsv;
import com.opencsv.bean.StatefulBeanToCsvBuilder;
import java.io.FileWriter;
import java.io.Reader;
import java.io.Writer;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class BeanExamples {
public static List<CsvBean> beanBuilderExample(Path path, Class clazz) {
ColumnPositionMappingStrategy ms = new ColumnPositionMappingStrategy();
return beanBuilderExample(path, clazz, ms);
}
public static List<CsvBean> beanBuilderExample(Path path, Class clazz, MappingStrategy ms) {
public static List<CsvBean> beanBuilderExample(Path path, Class<? extends CsvBean> clazz) throws Exception {
CsvTransfer csvTransfer = new CsvTransfer();
try {
ms.setType(clazz);
Reader reader = Files.newBufferedReader(path);
CsvToBean cb = new CsvToBeanBuilder(reader).withType(clazz)
.withMappingStrategy(ms)
try (Reader reader = Files.newBufferedReader(path)) {
CsvToBean<CsvBean> cb = new CsvToBeanBuilder<CsvBean>(reader)
.withType(clazz)
.build();
csvTransfer.setCsvList(cb.parse());
reader.close();
} catch (Exception ex) {
Helpers.err(ex);
}
return csvTransfer.getCsvList();
}
public static String writeCsvFromBean(Path path) {
try {
Writer writer = new FileWriter(path.toString());
public static String writeCsvFromBean(Path path) throws Exception {
StatefulBeanToCsv sbc = new StatefulBeanToCsvBuilder(writer).withSeparator(CSVWriter.DEFAULT_SEPARATOR)
List<CsvBean> sampleData = Arrays.asList(
new WriteExampleBean("Test1", "sample", "data"),
new WriteExampleBean("Test2", "ipso", "facto")
);
try (Writer writer = new FileWriter(path.toString())) {
StatefulBeanToCsv<CsvBean> sbc = new StatefulBeanToCsvBuilder<CsvBean>(writer)
.withQuotechar('\'')
.build();
List<CsvBean> list = new ArrayList<>();
list.add(new WriteExampleBean("Test1", "sfdsf", "fdfd"));
list.add(new WriteExampleBean("Test2", "ipso", "facto"));
sbc.write(list);
writer.close();
} catch (Exception ex) {
Helpers.err(ex);
sbc.write(sampleData);
}
return Helpers.readFile(path);
}
}

43
libraries-data-io/src/main/java/com/baeldung/libraries/opencsv/examples/sync/CsvReaderExamples.java
View File

@ -1,61 +1,58 @@
package com.baeldung.libraries.opencsv.examples.sync;
import com.baeldung.libraries.opencsv.helpers.Helpers;
import com.opencsv.CSVParser;
import com.opencsv.CSVParserBuilder;
import com.opencsv.CSVReader;
import com.opencsv.CSVReaderBuilder;
import java.io.Reader;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;
public class CsvReaderExamples {
public static List<String[]> readAll(Reader reader) {
public static List<String[]> readAllLines(Path filePath) throws Exception {
CSVParser parser = new CSVParserBuilder()
.withSeparator(',')
.withIgnoreQuotations(true)
.build();
CSVReader csvReader = new CSVReaderBuilder(reader)
try (Reader reader = Files.newBufferedReader(filePath)) {
CSVReaderBuilder csvReaderBuilder = new CSVReaderBuilder(reader)
.withSkipLines(0)
.withCSVParser(parser)
.build();
.withCSVParser(parser);
List<String[]> list = new ArrayList<>();
try {
list = csvReader.readAll();
reader.close();
csvReader.close();
} catch (Exception ex) {
Helpers.err(ex);
try (CSVReader csvReader = csvReaderBuilder.build()) {
return csvReader.readAll();
}
return list;
}
public static List<String[]> oneByOne(Reader reader) {
}
public static List<String[]> readLineByLine(Path filePath) throws Exception {
List<String[]> list = new ArrayList<>();
try {
CSVParser parser = new CSVParserBuilder()
.withSeparator(',')
.withIgnoreQuotations(true)
.build();
CSVReader csvReader = new CSVReaderBuilder(reader)
.withSkipLines(0)
.withCSVParser(parser)
.build();
try (Reader reader = Files.newBufferedReader(filePath)) {
CSVReaderBuilder csvReaderBuilder = new CSVReaderBuilder(reader)
.withSkipLines(0)
.withCSVParser(parser);
try (CSVReader csvReader = csvReaderBuilder.build()) {
String[] line;
while ((line = csvReader.readNext()) != null) {
list.add(line);
}
reader.close();
csvReader.close();
} catch (Exception ex) {
Helpers.err(ex);
}
}
return list;
}

25
libraries-data-io/src/main/java/com/baeldung/libraries/opencsv/examples/sync/CsvWriterExamples.java
View File

@ -9,26 +9,21 @@ import java.util.List;
public class CsvWriterExamples {
public static String csvWriterOneByOne(List<String[]> stringArray, Path path) {
try {
CSVWriter writer = new CSVWriter(new FileWriter(path.toString()));
for (String[] array : stringArray) {
writer.writeNext(array);
public static String writeLineByLine(List<String[]> lines, Path path) throws Exception {
try (CSVWriter writer = new CSVWriter(new FileWriter(path.toString()))) {
for (String[] line : lines) {
writer.writeNext(line);
}
writer.close();
} catch (Exception ex) {
Helpers.err(ex);
}
return Helpers.readFile(path);
}
public static String csvWriterAll(List<String[]> stringArray, Path path) {
try {
CSVWriter writer = new CSVWriter(new FileWriter(path.toString()));
writer.writeAll(stringArray);
writer.close();
} catch (Exception ex) {
Helpers.err(ex);
public static String writeAllLines(List<String[]> lines, Path path) throws Exception {
try (CSVWriter writer = new CSVWriter(new FileWriter(path.toString()))) {
writer.writeAll(lines);
}
return Helpers.readFile(path);
}

52
libraries-data-io/src/main/java/com/baeldung/libraries/opencsv/helpers/Helpers.java
View File

@ -1,9 +1,9 @@
package com.baeldung.libraries.opencsv.helpers;
import com.baeldung.libraries.opencsv.Constants;
import org.apache.commons.io.IOUtils;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.file.Path;
@ -13,9 +13,7 @@ import java.util.List;
public class Helpers {
/**
* Write Files
*/
// Write Files
public static Path fileOutAllPath() throws URISyntaxException {
URI uri = ClassLoader.getSystemResource(Constants.CSV_All).toURI();
@ -32,9 +30,7 @@ public class Helpers {
return Paths.get(uri);
}
/**
* Read Files
*/
// Read Files
public static Path twoColumnCsvPath() throws URISyntaxException {
URI uri = ClassLoader.getSystemResource(Constants.TWO_COLUMN_CSV).toURI();
@ -51,33 +47,12 @@ public class Helpers {
return Paths.get(uri);
}
/**
* Simple File Reader
*/
public static String readFile(Path path) {
String response = "";
try {
FileReader fr = new FileReader(path.toString());
BufferedReader br = new BufferedReader(fr);
String strLine;
StringBuffer sb = new StringBuffer();
while ((strLine = br.readLine()) != null) {
sb.append(strLine);
}
response = sb.toString();
System.out.println(response);
fr.close();
br.close();
} catch (Exception ex) {
Helpers.err(ex);
}
return response;
public static String readFile(Path path) throws IOException {
return IOUtils.toString(path.toUri());
}
/**
* Dummy Data for Writing.
*/
// Dummy Data for Writing
public static List<String[]> twoColumnCsvString() {
List<String[]> list = new ArrayList<>();
@ -94,15 +69,4 @@ public class Helpers {
return list;
}
/**
* Message Helpers
*/
public static void print(String msg) {
System.out.println(msg);
}
public static void err(Exception ex) {
System.out.println(Constants.GENERIC_EXCEPTION + " " + ex);
}
}

10
libraries-data-io/src/main/resources/csv/twoColumn.csv
View File

@ -1,5 +1,5 @@
colA, ColB
A, B
C, D
G, G
G, F
colA,colB
A,B
C,D
G,G
G,F
1 colA ColB colB
2 A B B
3 C D D
4 G G G
5 G F F

115
libraries-data-io/src/test/java/com/baeldung/libraries/opencsv/OpenCsvIntegrationTest.java
View File

@ -1,66 +1,107 @@
package com.baeldung.libraries.opencsv;
import com.baeldung.libraries.opencsv.helpers.Helpers;
import org.junit.After;
import org.junit.Before;
import com.baeldung.libraries.opencsv.beans.CsvBean;
import org.junit.Test;
import java.util.List;
import static org.assertj.core.api.Assertions.assertThat;
public class OpenCsvIntegrationTest {
private Object testReadCsv(Object result) {
assert (result != null);
assert (result instanceof String);
assert (!((String) result).isEmpty());
System.out.println(result);
return result;
}
private static final String NEW_LINE = System.lineSeparator();
private Object testWriteCsv(Object result) {
assert (result instanceof String);
assert (!((String) result).isEmpty());
return result;
}
@Test
public void givenSampleData_whenReadUsingPosition_thenContentsRead() throws Exception {
List<CsvBean> values = Application.simpleSyncPositionBeanExample();
@Before
public void setup() {
assertThat(values)
.extracting(Object::toString)
.containsExactly(
"colA,colB",
"A,B",
"C,D",
"G,G",
"G,F"
);
}
@Test
public void positionExampleTest() {
testReadCsv(Application.simpleSyncPositionBeanExample());
public void givenSampleData_whenReadUsingNamedColumn_thenContentsRead() throws Exception {
List<CsvBean> values = Application.namedSyncColumnBeanExample();
assertThat(values)
.extracting(Object::toString)
.containsExactly(
"Joe,27",
"Jane,32",
"Bob,53"
);
}
@Test
public void namedColumnExampleTest() {
testReadCsv(Application.namedSyncColumnBeanExample());
public void givenSampleData_whenReadLineByLine_thenContentsRead() throws Exception {
List<String[]> lineByLineContents = Application.readLineByLineSyncExample();
assertThat(lineByLineContents)
.containsExactly(
new String[] {"colA", "colB"},
new String[] {"A", "B"},
new String[] {"C", "D"},
new String[] {"G", "G"},
new String[] {"G", "F"}
);
}
@Test
public void writeCsvUsingBeanBuilderTest() {
testWriteCsv(Application.writeSyncCsvFromBeanExample());
public void givenSampleData_whenReadAllLines_thenContentsRead() throws Exception {
List<String[]> contents = Application.readAllLinesSyncExample();
assertThat(contents)
.containsExactly(
new String[] {"colA", "colB"},
new String[] {"A", "B"},
new String[] {"C", "D"},
new String[] {"G", "G"},
new String[] {"G", "F"}
);
}
@Test
public void oneByOneExampleTest() {
testReadCsv(Application.oneByOneSyncExample());
public void givenSampleData_whenWriteCsvUsingBean_thenContentsWritten() throws Exception {
String contents = Application.writeSyncCsvFromBeanExample();
assertThat(contents.split(NEW_LINE))
.containsExactly(
"'colA','colB','colC'",
"'Test1','sample','data'",
"'Test2','ipso','facto'"
);
}
@Test
public void readAllExampleTest() {
testReadCsv(Application.readAllSyncExample());
public void givenSampleData_whenWriteCsvLineByLine_thenContentsWritten() throws Exception {
String contents = Application.writeLineByLineSyncExample();
assertThat(contents.split(NEW_LINE))
.containsExactly(
"\"ColA\",\"ColB\",\"ColC\",\"ColD\"",
"\"A\",\"B\",\"A\",\"B\"",
"\"BB\",\"AB\",\"AA\",\"B\""
);
}
@Test
public void csvWriterOneByOneTest() {
testWriteCsv(Application.csvWriterSyncOneByOne());
public void givenSampleData_whenWriteCsvAllLines_thenContentsWritten() throws Exception {
String contents = Application.writeAllLinesSyncExample();
assertThat(contents.split(NEW_LINE))
.containsExactly(
"\"ColA\",\"ColB\",\"ColC\",\"ColD\"",
"\"A\",\"B\",\"A\",\"B\"",
"\"BB\",\"AB\",\"AA\",\"B\""
);
}
@Test
public void csvWriterAllTest() {
testWriteCsv(Application.csvWriterSyncAll());
}
@After
public void close() {
}
}